Emergency information in system information broadcast

ABSTRACT

A method and apparatus for handling emergency information for a wireless transmit receive unit (WTRU). The WTRU configured to receive scheduling information and receive a first transmission with a plurality of earthquake and tsunami warning system (ETWS) sub-system information blocks (sub-SIBs) of a first part of a ETWS-SIB based on the scheduling information, wherein the plurality of ETWS sub-SIBs of the first part include segments of a secondary ETWS message. The WTRU is further configured to receive a second transmission of a plurality of ETWS sub-SIBs of a second part of the second ETWS-SIB interspersed with non-EWTS system information, wherein the plurality of ETWS sub-SIBs of the second part include segments of the secondary ETWS message. The WTRU is further configured to recover the secondary ETWS message from the first and second part of the second ETWS-SIB and then display the recovered secondary ETWS message via a user interface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 14/671,072 filed Mar. 27, 2015, which is a continuation of U.S.Non-Provisional application Ser. No. 12/486,029 filed Jun. 17, 2009,which issued on Apr. 14, 2015 as U.S. Pat. No. 9,008,605, which claimsthe benefit of Provisional Application No. 61/074,229 filed Jun. 20,2008, which are incorporated by reference as if fully set forth.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

The Third Generation Partnership Project (3GPP) has initiated the LongTerm Evolution (LTE) program to bring new technology, new networkarchitecture, new configurations and new applications and services towireless networks in order to provide improved spectral efficiency andfaster user experiences.

FIG. 1 shows an overview of an Evolved Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access Network(E-UTRAN) 100 in accordance with the prior art. As shown in FIG. 1,E-UTRAN 100 includes three eNodeBs (eNBs) 102, however, any number ofeNBs may be included in E-UTRAN 100. The eNBs 102 are interconnected byan X2 interface 108. The eNBs 102 are also connected by an S1 interface106 to the Evolved Packet Core (EPC) 104 that includes a MobilityManagement Entity (MME) 112 and a Serving Gateway (S-GW) 110.

System information (SI) is information that is broadcast within a celland provides information about configurations and parameters that arecommon to at least some of the wireless transmit receive units (WTRUs)in the cell.

System information messages may include parameters such as networkidentification, neighbouring cells, channel availability and powercontrol requirements, for example.

An LTE network may include a severe earthquake and tsunami warningservice (ETWS). The ETWS may warn wireless telephone users of animminent or nearby man-made or natural disaster. In the LTE radio accessnetwork, ETWS information is distributed via system informationbroadcast.

SUMMARY

A method and apparatus for handling emergency information for a wirelesstransmit receive unit (WTRU). The WTRU configured to receive schedulinginformation and receive a first transmission with a plurality ofearthquake and tsunami warning system (ETWS) sub-system informationblocks (sub-SIBs) of a first part of a ETWS-SIB based on the schedulinginformation, wherein the plurality of ETWS sub-SIBs of the first partinclude segments of a secondary ETWS message. The WTRU is furtherconfigured to receive a second transmission of a plurality of ETWSsub-SIBs of a second part of the second ETWS-SIB interspersed withnon-EWTS system information, wherein the plurality of ETWS sub-SIBs ofthe second part include segments of the secondary ETWS message. The WTRUis further configured to recover the secondary ETWS message from thefirst and second part of the second ETWS-SIB and then display therecovered secondary ETWS message via a user interface.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1 shows an overview of an E-UTRAN in accordance with the prior art;

FIG. 2 shows an example wireless communication system including aplurality of WTRUs and an eNB in accordance with one embodiment;

FIG. 3 is a block diagram of a WTRU and the eNB of FIG. 2;

FIG. 4 shows a method of non-overlapping emergency SI messagetransmission in accordance with one embodiment; and

FIG. 5 shows a method of overlapping transmission of emergency SImessages in accordance with another embodiment.

DETAILED DESCRIPTION

When referred to hereafter, the term “wireless transmit/receive unit(WTRU)” includes, but is not limited to, a user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a computer, or any othertype of user device capable of operating in a wireless environment. Whenreferred to hereafter, the term “base station” includes, but is notlimited to, a Node B, a site controller, an access point (AP), or anyother type of interfacing device capable of operating in a wirelessenvironment.

FIG. 2 shows a wireless communication system 200 including a pluralityof WTRUs 210 and an e Node B (eNB) 220. As shown in FIG. 2, the WTRUs210 are in communication with the eNB 220. Although three WTRUs 210 andone eNB 220 are shown in FIG. 2, it should be noted that any combinationof wireless and wired devices may be included in the wirelesscommunication system 200.

FIG. 3 is a functional block diagram 300 of a WTRU 210 and the eNB 220of the wireless communication system 200 of FIG. 2. As shown in FIG. 2,the WTRU 210 is in communication with the eNB 220. The WTRU 210 isconfigured to receive and process emergency and non-emergency SImessages.

In addition to the components that may be found in a typical WTRU, theWTRU 210 includes a processor 315, a receiver 316, a transmitter 317,and an antenna 318. The WTRU 210 may also include a user interface 321,which may include, but is not limited to, an LCD or LED screen, a touchscreen, a keyboard, a stylus, or any other typical input/output device.The WTRU 210 may also include memory 319, both volatile and non-volatileas well as interfaces 320 to other WTRU's, such as USB ports, serialports and the like. The receiver 316 and the transmitter 317 are incommunication with the processor 315. The antenna 318 is incommunication with both the receiver 316 and the transmitter 317 tofacilitate the transmission and reception of wireless data.

In addition to the components that may be found in a typical eNB, theeNB 220 includes a processor 325, a receiver 326, a transmitter 327, andan antenna 328. The receiver 326 and the transmitter 327 are incommunication with the processor 325. The antenna 328 is incommunication with both the receiver 326 and the transmitter 327 tofacilitate the transmission and reception of wireless data. The eNB 220is configured to transmit and process emergency and non-emergency SImessages.

A natural or man-made disaster may occur within an area that is servedby a wireless telephone service. Users located in a particular servingcell area may require immediate information and/or evacuation. If so,emergency system information messages may be used to transmit emergencyinstructions and information to users in the affected areas, such asevacuation information, for example. The emergency system informationmessages may also be used to inform users adjacent to the evacuationarea that an emergency is occurring, and to inform users who are locatedin an area not directly affected by the emergency, but who may requireinformation updates regarding the disaster.

The system information can include an emergency information indicator.The emergency information indicator may be, for example, a flag, aparticular bit or string of bits that may indicate the type of emergencyinformation being received by the WTRU. The emergency informationindicator may be placed, for example, in the cell entries in theneighboring cell list or a block list.

Emergency information may require larger data bandwidth for possibledisaster handling, that is, more resource blocks, than non-emergencyinformation. Due to the relatively large size of emergency information,a WTRU may require larger resources to receive the necessary emergencyinformation. Emergency information indicators are carried in systeminformation, which is carried on a downlink shared channel, such as thephysical downlink shared channel (PDSCH), for example. Resources for thePDSCH are carried on a downlink control channel, such as the physicaldownlink control channel (PDCCH). The resource scheduling for emergencyinformation may be different than the scheduling required fornon-emergency information due to the relatively large size of theemergency information. This may require the use of a number scalerepresentation or format that is different from that used fornon-emergency information resource scheduling.

Therefore a specialized ETWS radio network temporary identifier(ETWS_RNTI) may be used with emergency information notification, and maybe used to obtain the PDSCH resources for reading the system informationblocks (SIBs) carrying emergency information notification. A radionetwork temporary identifier (RNTI) may be used to identify a WTRU whena radio resource control (RRC) connection is present, or used toidentify special network service information available to all the WTRUs.The ETWS_RNTI may be used to identify to all WTRUs that network orpublic emergency information is available for retrieval. As emergencyinformation may be broadcast with a primary notification and a secondarynotification, the ETWS_RNTI may be used to receive emergency informationwhen the primary ETWS notification is on, and may take higher prioritythan other RNTI signal processing.

Non-emergency SIB transmission is periodic. Emergency information SIBtransmission may also have a particular period (T_(ETWS-SI)). The periodmay be at least, for example, 128 or 256 frames, so that transmission iseasier and to accommodate potential retransmission segments.Furthermore, the emergency information SI transmission may employ avoluntary retransmission scheme that automatically sends redundantinformation without waiting for a negative acknowledgement signal (NACK)so that each WTRU can reliably receive the emergency information SIB(s)in one defined period.

Non-emergency SI messages are transmitted within periodically occurringtime domain windows using dynamic scheduling. Each SI message isassociated with a SI-window. SI-windows containing different SI messagesdo not overlap. That is, within one SI-window only the corresponding SImessage is transmitted. The length of the SI-window is common for all SImessages, and is configurable. Within the SI-window, the correspondingSI message can be transmitted a number of times in any subframe. TheWTRU may acquire the detailed time and frequency domain scheduling fromdecoding the SI-RNTI on the PDCCH.

In one embodiment, emergency SI messages may be scheduled in anon-overlapping manner, which means that emergency SI messages andnon-emergency SI messages are not transmitted simultaneously.Non-overlapping emergency SI message transmission may be scheduled atthe same time, interleaved as segments, as with non-emergency SI messagetransmission. The emergency SI messages may be carried in relativelysmall consecutive sub-frames that are not significantly larger than thenon-emergency SI transmission window length. The transmission ofemergency SI messages may be scheduled according to the formula:

SFN mod T _(ETWS-SI)=0 and X=(n−1)*Y;  Equation (1)

wherein T_(ETWS-SI) is the emergency SI message periodicity, X is thenon-emergency SI message offset, n is the number of non-emergency SImessages and Y is periodicity of the non-emergency SI messages.

The emergency SI information messages may be placed in at the end of thenon-emergency SI messages. Alternatively, the emergency SI messages canbe placed in the beginning or in the middle of the non-emergencymessages. The location of the emergency SI messages may be signaled tothe WTRU in a system information block, such as SIB-1, for example.

An offset (ETWS_Offset denoted as X_(ETWS-SI)) can be applied to theemergency SI messages. The ETWS_Offset allows the transmission of theemergency SI messages without overlapping non-emergency SI messages.

SFN mod T _(ETWS-SI) =X _(ETWS-SI)  Equation (2)

where the X_(ETWS-SI) is a frame offset [0, . . . , P] for the emergencySI messages and P is the shortest periodicity among all SIs. TheX_(ETWS-SI) could be signaled from the network.

FIG. 4 shows a method of non-overlapping emergency SI messagestransmission 400 in accordance with one embodiment. The emergency SImessages 402 are transmitted after the non-emergency SI messages 404.

Alternatively, emergency SI messages may be transmitted up to a pointwhere the non-emergency SI messages begin. No offset is required. Ifthere are more emergency SI messages to be transmitted after thenon-emergency SI message point is reached, the balance of the emergencySI messages may be transmitted as segments between the non-emergency SImessages. The emergency SI message segments may be transmitted insub-frames in the T_(ETWS-SI) period that do not contain non-emergencySI messages. The WTRU may receive a signal from a network node, such asan eNodeB, for example, that contains an indication as to which of thesub-frames to use. The indication may be a bitmap, for example.Alternatively, the WTRU may receive the indication in a primary ETWSnotification message or an SIB, such as SIB-1 for example.

The Tx-window-size for emergency SI messages (Y_(ETWS-SI)) can be madeequal to or less than the Tx-window size of non-emergency SI messages(Y) if more frequency spectrum bandwidth, or resource blocks (RBs), canbe assigned to transmit the emergency SI messages. Y_(ETWS-SI) can besignaled and transmitted in an SIB, such as SIB-1, for example. It maybe signaled only when the primary ETWS notification is activated or canbe always be part of the SIB. Alternatively, Y_(ETWS-SI) can also besent in the primary ETWS notification message or in a paging messageused to indicate that a change in system information is upcoming.

If the emergency SI messages are scheduled to be transmitted in thebeginning or in the middle of the non-emergency SI messages, andY_(ETWS-SI) is not the same as Y, then the offset X=(n−1)*Y can becomputed as:

X=(n−2)*Y for n before n′ of the ETWS SI, or

X=(n′−2)*Y+Y _(ETWS-SI)+(n−1−n′)*Y; for n after n′.

In another embodiment, emergency SI messages may be broadcast overlappedwith non-emergency SI messages. This means that an anticipated largevolume of emergency data may be handled by WTRUs configured to receiveemergency SI messages while the WTRU is also receiving a non-emergencysignal.

Transmission of emergency SI messages may be concentrated ordistributed. If the transmission is concentrated, consecutive sub-framesmay be equal to or larger than Y, the non-emergency SI Tx-window-size.The scheduling of emergency SI messages may not be restricted bynon-emergency SI messages, as defined by the equation:

SFN mod T _(ETWS-SI) =X _(ETWS-SI),

where X_(ETWS-SI) is a frame offset (0, . . . , P).

If transmission of emergency SI messages is distributed, the emergencySI messages may be segmented into SIBs and/or sub-SIBs based on thecontent and size of the emergency SI message. The emergency informationSI transmission unit may use M consecutive sub-frames with J RBs each,where M and J are integers, such that the amount of data transmittedequals J*M for each emergency information receiving occasion. The totalsize of the emergency SI message includes the size of any retransmissionredundancy, if scheduled. The number of reception occasions(O_(ETWS-IS)) equals ceiling[total ETWS-SI size div (J*M)]. If J varies,then the number of reception occasions equals ceiling[(T_(ETWS-SI)×10)div M in subframes].

FIG. 5 shows a method of overlapping transmission of emergency SImessages 500 in accordance with another embodiment. The emergency SImessages 502 are segments and are evenly distributed throughout theemergency SI message period T_(ETWS) 506. The emergency SI messages 502are overlapped with the non-emergency SI messages 504.

The distance between the start of two emergency information Tx-windowsbetween repeat transmission occasions is known as the Occasion frameoffset (ETWS-OF). In units of sub-frames, ETWS-OF=(T_(ETWS-SI)*10) divO_(ETWS-IS). Alternatively, the ETWS-OF may be configured such thatETWS-OF*(O_(ETWS-IS))<=(T_(ETWS-SI)*10).

The reception occasions for a WTRU are at frames, starting at SFN modT_(ETWS-SI)=X_(ETWS-SI), defined by the equation:

[X _(ETWS-SI) ,X _(ETWS-SI)+(O _(ETWS-IS)−1)*ETWS-OF/10,X_(ETWS-SI)+(2*ETWS-OF)/10,X _(ETWS-SI)+(3*ETWS-OF)/10, . . . ,X_(ETWS-SI)+(O _(ETWS-IS)−1)*ETWS-OF/10].

The subframe offset in the respective frame is equal to (n*ETWS-OF) mod10.

Emergency SI message segments can be transmitted over non-emergencytraffic in a specified pattern. The pattern can be signaled in an SIB,such as SIB-1, for example, starting at a frame defined by:

SFN mod T _(ETWS-SI) =X _(ETWS-SI).

The pattern may be Ax+By+Cz+ . . . where A, B and C . . . are the numberof repeated occurrences of offset-x, offset-y and offset-z respectively,such that A+B+C>=O_(ETWS-IS). For example, the signaling may show thatA=3, B=1, C=5, x=24, y=40, z=38. This indicates that from the start,there will be three transmission occurrences in occurrence group A. Thestart of the second occurrence in occurrence group A is 24 sub-framesfrom the beginning of the first occurrence. There is one occurrence inoccurrence group B, which is 40 sub-frames from the beginning of thelast occurrence of occurrence group A, and the five occurrences inoccurrence group C are each 38 sub-frames from the beginning of the lastoccurrence. Given the patterned distribution, one ETWS-RNTI may be ableto describe all emergency SI message reception occasions and resourceblock (RB) allocations. It is used only when the primary ETWSnotification is ON.

The PDCCH format to describe the ETWS-SI resources can be in a formatsimilar to PDCCH format 1C, which is currently used to for random accesschannel (RACH) response, paging, and notification of dedicated broadcastchannel (D-BCH). The PDCCH format used for the ETWS-SI will multiply theETWS-RNTI on the cyclic redundancy check (CRC) of the PDDCH. Hence, whenthe UE decodes the PDCCH, it can verify whether their PDCCH is addressedto the ETWS-RNTI.

Although features and elements are described above in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

What is claimed is:
 1. A method for use in a wireless transmit/receiveunit (WTRU), the method comprising: receiving scheduling information;receiving a first transmission with a plurality of earthquake andtsunami warning system (ETWS) sub-system information blocks (sub-SIBs)of a first part of an ETWS-SIB based on the scheduling information,wherein the plurality of ETWS sub-SIBs of the first part includesegments of a secondary ETWS message; receiving a second transmission ofa plurality of ETWS sub-SIBs of a second part of the second ETWS-SIBinterspersed with non-EWTS system information based on the schedulinginformation, wherein the plurality of ETWS sub-SIBs of the second partinclude segments of the secondary ETWS message; recovering the secondaryETWS message from the first part of the second ETWS-SIB and the secondpart of the second ETWS-SIB; and displaying the recovered secondary ETWSmessage.
 2. The method of claim 1, wherein the secondary ETWS message iscarried on a downlink shared channel.
 3. The method of claim 1, whereinthe secondary ETWS message is sent periodically.
 4. The method of claim1, further comprising receiving a paging message indicating thesecondary ETWS message.
 5. The method of claim 1, wherein at least onebit indicates the type of message of the secondary ETWS message.
 6. Awireless transmit/receive unit (WTRU) comprising: a receiver coupled toa processor, the receiver and processor configured to receive schedulinginformation and receive a first transmission with a plurality ofearthquake and tsunami warning system (ETWS) sub-system informationblocks (sub-SIBs) of a first part of a ETWS-SIB based on the schedulinginformation, wherein the plurality of ETWS sub-SIBs of the first partinclude segments of a secondary ETWS message; the receiver and processorfurther configured to receive a second transmission of a plurality ofETWS sub-SIBs of a second part of the second ETWS-SIB interspersed withnon-EWTS system information, wherein the plurality of ETWS sub-SIBs ofthe second part include segments of the secondary ETWS message; a memorycoupled to the processor, the memory and processor configured to storethe scheduling information, the first transmission, and the secondtransmission and recover the secondary ETWS message from the first partof the second ETWS-SIB and the second part of the second ETWS-SIB; and auser interface configured to display the recovered secondary ETWSmessage.
 7. The WTRU of claim 6, wherein the secondary ETWS message iscarried on a downlink shared channel.
 8. The WTRU of claim 6, whereinthe secondary ETWS message is sent periodically.
 9. The WTRU of claim 6,wherein the processor and transceiver is further configured to receive apaging message indicating the secondary ETWS message.
 10. The WTRU ofclaim 6, wherein at least one bit indicates the type of message of thesecondary ETWS message.